Abstract

The vegetal pole cytoplasm represents a crucial source of maternal dorsal determinants for patterning the dorsoventral axis of the early embryo. Removal of the vegetal yolk in the zebrafish fertilised egg before the completion of the first cleavage results in embryonic ventralisation, but removal of this part at the two-cell stage leads to embryonic dorsalisation. How this is achieved remains unknown. Here, we report a novel mode of maternal regulation of BMP signalling during dorsoventral patterning in zebrafish. We identify Vrtn as a novel vegetally localised maternal factor with dorsalising activity and rapid transport towards the animal pole region after fertilisation. Co-injection of vrtn mRNA with vegetal RNAs from different cleavage stages suggests the presence of putative vegetally localised Vrtn antagonists with slower animal pole transport. Thus, vegetal ablation at the two-cell stage could remove most of the Vrtn antagonists, and allows Vrtn to produce the dorsalising effect. Mechanistically, Vrtn binds a bmp2b regulatory sequence and acts as a repressor to inhibit its zygotic transcription. Analysis of maternal-zygotic vrtn mutants further shows that Vrtn is required to constrain excessive bmp2b expression in the margin. Our work unveils a novel maternal mechanism regulating zygotic BMP gradient in dorsoventral patterning.

This work was supported by grants from the National Natural Science Foundation of China (31101038 to M.S., 31471360 and 31671509 to D.-L.S), Shandong University and the Groupement des Entreprises Françaises dans la Lutte contre le Cancer (GEFLUC Paris-Ile de France) to D.-L.S.

Data availability

The RNA-seq data supporting this work are available from Gene Expression Omnibus with accession number GSE103090.

Log in using your username and password

Log in through your institution

You may be able to gain access using your login credentials for your institution. Contact your library if you do not have a username and password.

If your organization uses OpenAthens, you can log in using your OpenAthens username and password. To check if your institution is supported, please see this list. Contact your library for more details.

Pay Per Article - You may access this article (from the computer you are currently using) for 1 day for US$30.00 .

Regain Access - You can regain access to a recent Pay per Article purchase if your access period has not yet expired.

Other journals from The Company of Biologists

Various aspects of animal development are influenced by the host's microbiota. For instance, zebrafish reared in a germ-free environment show abnormal cell fate allocation in the intestine, but whether this process is linked to Notch signalling was previously unclear. Now, Karen Guillemin, Judith Eisen and colleagues combine gnotobiotic and genetic manipulations to test this relationship.

In this poster and accompanying article, Joseph J. Kieber and G. Eric Schaller summarise the current understanding of cytokinin metabolism, transport and signalling, and discuss how this phytohormone regulates changes in gene expression to mediate its pleiotropic effects.

You can actually ask questions that people have not asked before in systems that have not been used before

New Development Editor Ykä Helariutta heads groups working on vascular development in plants and trees at both the University of Helsinki and the University of Cambridge. He shares how his career in plant gene discovery and mapping was a natural evolution of his childhood interest in plant taxonomy, and the benefits of taking risks with non-model organisms.

preLights, the community-led biology preprints highlight service hosted by The Company of Biologists, launched on February 20th. To find out more about preLights, read the Editorial by our Editor-in-Chief Olivier Pourquié and Executive Editor Katherine Brown.

You Wu and Mineko Kengaku, from the Institute for Integrated Cell-Material Sciences at Kyoto University, share the story of how they used live imaging to understand the process of neuronal migration. This approach revealed some fascinating cellular behaviours, as described their recent Research Article published in Development .